2004 jetta cranks but wont start

I have a 2004 jetta and have been having problems for two weeks now. At first the car would start the first time starting it of a morning. Then it would just sit and crank if I tried starting it while the engine still had heat built up. I have been trying to figure out the problem and now the last couple of days the car will not start at all. Could someone help lead me in the right direction to fix this?

I haven't checked the error codes yet, i do not know what the timing belt timing is and the recent maintenance is new fuel filter new air filter and crank sensor. I was having trouble with it dying while driving the car for over a 30 minutes or so but always started right back up. Replaced the crank sensor and was fine for 3 weeks and then this started.